That particularly vicious yellow-green type of liquid shit that stings your ring piece with such ferocity that immediate submersion in water is needed to cool the pain. Often brought on by over indulgence in chilli and other types of hot food, this is the bile and acid left over from the gastric digestive juices that are designed to break down food within the protection of the stomach’s walls. As it exits from your own back door area you feel a pain guaranteed to make you scream and blubber with each gush.

From the Latin: Acidicus Extremus Rectalis

“Dude – I feasted on some hot wings last night that burned me bad on the way out. But after the normal turd session, I had a bout of shitacid that left me screaming like a baby. I think I ripped myself a wider slot back there for sure.”
From the original screenplay of “Dude, my ring is ringing”

“What ho Jeeves, I was due to play a round of badminton this afternoon with Field Marshall Mountbatten, but I fear a torrent of shitacid might be about to visit my back passage at any moment. What say you attend with us and bring a wad of damp towels with you in case I have to rip out a beastly stream at some stage during the game?”
From Jeeves & Wooster Play Shuttlecock and Balls